Many communication systems include devices that communicate synchronously with one another. For example, some memory components utilize a strobe signal to provide source synchronous clocking events for read and write information on the data signals. Unfortunately, as the signaling or data rate is increased in such systems delays between these signals may occur.
In particular, the total communication path length between memory components is often relatively long. In the case of a read operation, the complete path includes generating the read command and address information in the clock domain of a memory controller (which is referred to as a PClk domain), transmitting this information across interconnect links between the memory controller and a memory device, receiving the information at the memory device, performing the read operation, transmitting read data signals and a corresponding strobe signal across the interconnect links to the memory controller, and receiving the read data using the strobe signal at the memory controller. This communication path includes various delays that may change as conditions vary, for example, there may be variations in temperature or a supply voltage.
The resulting delays between the data signals and the strobe signals may make it difficult for the memory controller to determine when a timing event on the strobe indicates the presence of read data, as opposed to noise. Existing approaches to this challenge include manual tuning of strobe-enable-window circuits to achieve reasonable timing for each system and silicon process. However, such adjustments are fixed, are time consuming and difficult to perform, and have limited efficacy. As such, these approaches sacrifice timing margin. In addition, these approaches may not be capable of supporting systems that have unmatched strobe drifts greater than ±1 bit time.
There is a need, therefore, for improved timing drift cancellation circuits and techniques that reduce and/or eliminating timing drift between data signals and strobe signals without the aforementioned problems.
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